Field Flattener for visual use..?

[Fozzie]

morning everyone,

Can some one please educate me, because i'm drawing a blank.

I've recently acquired myself a 72mm F6 Ed frac, which I'm expecting to suffer from a degree of FC as has been mentioned in other threads.  It was certainly slightly evident during some WL viewing yesterday, and in the 24mm 68Deg ES last night.

Now on investigating, say the 1x FF from Altair for F6 refractors, most appear to have a 2" nose piece on one end (I know where to stick this bit) and on the other they mainly appear to be threaded for DSLR connection.

Am I missing something or another adapter to use for visual  , or (thinking as i'm typing) do I unscrew the 2" barrel on the diagonal and attach this way..?   

I'm not going to jump in and buy one, but knowing the answer would be great!

Thanks

Fozzie

[michael.h.f.wilkinson]

I have used a TS flattener (which came with spaces and T2 mount attached, but they unscrew) screwed into the front end of a 2" diagonal in my 80mm F/6 triplet. That only roughly gets the right distance to the EP (Nagler 22T4 and 31T4 mainly), so I started observing without. I found I had no problems with this, as the eye will accommodate enough to deal with the field curvature in my case

[Fozzie]

Thanks Michael, useful to know that it does all go together..

I suspect it would be a bad idea of using one in front of a lunt wedge for WL anyway, and most appear to be 2" FF while thinking about it my Wedge is 1.25.. so not much help I guess, unless using a reducer.

Thanks

Fozzie

[Stu]

I've used the TS flattener too, still have it in fact but don't tend to use it much any more, mainly because the only scope I have which exhibits field curvature would probably be the Tak 60 and I tend just to use 1.25" eyepieces in this, or for solar.

As Michael says, it needs some adjustment of spacing to get exactly right, but I tended just to screw it onto the diagonal, same as Michael. It makes more difference with ultra wide eyepieces like Ethos etc.

[Fozzie]

Thanks Stu,

Widest EP's i'ce got are the 24mm 68deg (1,25) and the 18mm 82deg ES range, giving 3.8deg and 3.4deg respectively.. I noticed the FC in these last night, but wasn't overly distracted by it if im honest. 

Did notice it in the 12mm SLV during WL as the active region just coming in to view was definitely out by a small turn on the fine adjustment.

Any ways, thanks for the response chaps..

Oh look 500 posts up now too!

Thanks

Fozzie

[michael.h.f.wilkinson]

Thanks Michael, useful to know that it does all go together..

I suspect it would be a bad idea of using one in front of a lunt wedge for WL anyway, and most appear to be 2" FF while thinking about it my Wedge is 1.25.. so not much help I guess, unless using a reducer.

Thanks

Fozzie

It would be a VERY bad idea to put it in front of the Lunt Wedge! I am not sure you will need a flattener for solar. I usually have a PowerMate or TeleXtender between wedge and camera, and that works fine. I never use the field flattener for solar, nor do I feel it is needed